Many paperboard products are coated with a high-gloss coating to provide a high-gloss, water-resistant finish. The finish may be applied merely for aesthetic purposes. In other cases, however, the high-gloss, water resistance serves a very functional purposes, e.g., coatings of paper cups allow them to hold water and other liquids.
Currently, the high-gloss, water-resistant coatings most commonly used for paperboard products, such as paper cups, are wax or polyethylene. These coatings are food-compatible, meeting U.S. government standards and substantially all other government standards for food-contact compatibility. However, a significant drawback of wax and polyethylene are that they render the paper product non-recyclable. Neither wax nor polyethylene coatings are broken down by common pulping bath chemicals and remain as a glob or film when the coated paper product is placed in the pulping bath. Such films or globs tend to interfere with processing of the pulp; thus, paper products coated with polyethylene or waxes are generally rejected for recycling.
Accordingly, it is a general object of the invention to provide a coating for paper products, particularly paperboard, which meets governmental requirements for food contact, particularly those of U.S.C. 21 C.F.R. section 176.170 (Food and Drug Administration), commonly referred in the industry as 176/170 compliance and which is fully pulpable such that the paper product which is coated may be subsequently recycled.